ENGLISH
REFERENCE

fly

v. · n. · adj.
US //ˈfɫaɪ// UK //flˈaɪ// fly
Irregular verb past flew past participle flown
  1. 1 to move through the air (v.)
    A1 Beginner

    to move through the air using wings or an aircraft.

    to move through the air or space under one's own power or by means of an aircraft. Intransitive in this sense.

    Example

    The birds fly south every year when the weather starts to get cold.

    Example

    The pilot managed to fly the damaged aircraft through the storm, landing safely despite the failing engine.
    Pitfall
    The bird has flied away.
    The bird has flown away.

    The verb 'fly' is irregular: fly, flew, flown.

  2. 2 to move very fast (v.)
    B1 Intermediate Informal

    to move or go somewhere very quickly.

    to move, pass, or progress with great speed or haste.

    Example

    I have to fly or I will be late for my doctor's appointment.

    Example

    Time seemed to fly during the summer holidays, leaving the students unprepared for the sudden return to their studies.

    Teacher's tip

    Often used with 'time' to express how quickly a period has passed.
Show 6 more sensesShow fewer
  1. 3 to be accepted (v.)
    B2 Upper Intermediate Informal

    to be successful or accepted by other people.

    to be valid, acceptable, or successful in a particular context.

    Example

    That excuse about your dog eating your homework just won't fly with the teacher.

    Example

    The board of directors made it clear that the proposed budget cuts simply would not fly in the current economic climate.

    Usage

    Usually used in the negative to mean a plan or excuse will not be believed.
  2. 4 to display a flag (v.)
    B1 Intermediate

    to show a flag by hanging it from a pole.

    to display a flag or banner from a pole or mast. Transitive use.

    Example

    The ship was flying a red flag to warn other boats of the danger.

    Example

    Every government building in the capital was required to fly the national colours during the independence celebrations.
  3. 5 the insect (n.)
    A2 Elementary zoology

    a small insect with two wings that often makes a buzzing sound.

    any two-winged insect of the order Diptera, specifically the common housefly.

    Example

    A fly was buzzing around the kitchen while I was trying to cook dinner.

    Example

    The biologist observed the fly under the microscope to study the intricate structure of its compound eyes.

    Usage

    The plural is 'flies'.
    • housefly
  4. 6 trousers opening (n.)
    B1 Intermediate

    the opening at the front of a pair of trousers that uses a zipper or buttons.

    an opening at the crotch of a pair of trousers, typically closed by a zipper or buttons and covered by a fabric flap.

    Example

    He realized his fly was open just as he walked onto the stage.

    Example

    The tailor carefully stitched the fly of the bespoke trousers to ensure the buttons remained hidden behind the silk placket.

    Usage

    Often used in the plural 'flies' in British English, but singular 'fly' in American English.
  5. 7 fishing lure (n.)
    C1 Advanced Technical fishing

    a fake insect used as bait to catch fish.

    an artificial fishing lure made of silk, feathers, or similar material to resemble an insect.

    Example

    He spent the afternoon choosing the right fly to catch trout in the river.

    Example

    Experienced anglers often tie their own flies, meticulously matching the local insect population to increase their chances of a strike.
  6. 8 stylish (adj.)
    C1 Advanced Slang Informal

    looking very cool, stylish, or attractive.

    stylish, fashionable, or physically attractive. Primarily used in urban contexts.

    Example

    Those new sneakers you bought are looking really fly.

    Example

    He showed up to the party looking fly in a vintage leather jacket and designer sunglasses.

    Teacher's tip

    This term was very popular in 1990s hip-hop culture; it is still used but can feel slightly dated to some speakers.
Etymology 1

From Middle English flye, flie, from Old English flȳġe, flēoge (“a fly”), from Proto-West Germanic fleugā, from Proto-Germanic fleugǭ (“a fly”), from Proto-Indo-European *plewk- (“to fly”). Cognate with Scots flee, Saterland Frisian Fljooge, Dutch vlieg, German Low German Fleeg, German Fliege, Danish flue, Norwegian Bokmål flue, Norwegian Nynorsk fluge, Swedish fluga, Icelandic fluga.

Etymology 2

From Middle English flien, from Old English flēogan, from Proto-West Germanic fleugan, from Proto-Germanic fleuganą, from Proto-Indo-European plewk- (plew-k-, “to fly”), enlargement of *plew- (“flow”). Compare Etymology 1. See also Saterland Frisian fljooge, Dutch vliegen, Low German flegen, German fliegen, Danish flyve, Norwegian Nynorsk flyga; also Lithuanian plaũkti ‘to swim’). More at flee and flow.

Etymology 3

From Middle English flye (“flying, flight”), from Old English flyge (“flying, flight”), from Proto-Germanic *flugiz.

Etymology 4

Uncertain; probably from the verb or noun.

Etymology 5

Related to German Flügel (“a wing”), Dutch vleugel (“a wing”), Swedish flygel (“a wing”).

Word family
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